The regulation of biosynthesis of the cell wall will be examined in two model systems - Bacillus subtilis, and Staphylococcus aureus. Cell wall mutants will be isolated using osmotic stabilization and temperature shifts to obtain these conditional lethal mutants. The biochemical defect will be determined and the mutants mapped by DNA- mediated transformation and transduction. Other mutants entirely deficient in cell walls (L-forms) will be included in the study.